CA1147026A - Program control device for controlling flash butt welding process - Google Patents
Program control device for controlling flash butt welding processInfo
- Publication number
- CA1147026A CA1147026A CA000361564A CA361564A CA1147026A CA 1147026 A CA1147026 A CA 1147026A CA 000361564 A CA000361564 A CA 000361564A CA 361564 A CA361564 A CA 361564A CA 1147026 A CA1147026 A CA 1147026A
- Authority
- CA
- Canada
- Prior art keywords
- welding
- program control
- output
- inputs
- ups
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
Abstract of the Disclosure A device of the invention comprises welding current pick-ups switched into each welding circuit.
Outputs of the said welding current pick-ups are conn-ected to a logical coincidence means generating its output signal provided so that to all its inputs are applied signals. The said output signal starts a welding program control means controlling a drive adapted for moving the workpieces being welded. The proposed device permits a flashing allowance of the workpieces being welded to be decreased, and the effic-iency of the process and the quality of the resulting weld joints to be improved.
Outputs of the said welding current pick-ups are conn-ected to a logical coincidence means generating its output signal provided so that to all its inputs are applied signals. The said output signal starts a welding program control means controlling a drive adapted for moving the workpieces being welded. The proposed device permits a flashing allowance of the workpieces being welded to be decreased, and the effic-iency of the process and the quality of the resulting weld joints to be improved.
Description
7g~
The present invention relates to ~lash butt welding~ and particularl~ to apparatu~ Por program control of flash butt .velding.
Most efficientl~ the invention can be used in simultaneous-1~ welding several join-ts, as well as in welding articles having long seams to be formed, such a , for example~ metal s~eets measu-ring several meters in width and pipes of large diameters.
'~here is known a program control device ~or controlling a ~lash bu-tt welding process (cf. U~SR Author's Certi~icate ~o. 557~889) comprising welding culren-t pick-ups switched into each welding circuit, and a welding program controlling unit havin~ a power suppl~ circuit and being connec-ted through its output with a drive for moving workpieces being welded. ~his device ~ur-ther includes a peak s;Lgnal de-tector having inpu-ts connected to outputs o~ the welding current pick-ups and an out-put connected, through a parallel-connected proportional and r~al dif~eren-tiating elemen-ts, to a comparator unit.
This prior art device opera-t;es as ~ollows. A preset current magnitude ~rom a pic~-up~ an actual current magnitude, and a time deri~ative thereo~ ara applied to the comparator unit.
'~he ampli~ied signal from the comparator unit is fed to the : welding program con~rol unit controlling the drive ~or moving the woxkpieces being welded. It is to be noted that the speed of approach o~ the wor~pieces is propor-tional to the said signal.
Thus, t~e operation o~ the above device consis-ts in detect-ing a maximal magnitude o~ the current densi-ty in one of t~e parallel circuits, and in controlling the welding process to "~
0~
maintain s-tability thereof bas-ing on the said maximal magnitude of the current density.
However, in the case of using the prior art device, a starting flashing allowance has to be increased.
Moreover the welding time has also to be increased to compensate for an irregular preparation of abutting ends of the workpieces to be welded together, which in the end brings down the efficiency of the welding process.
In addition non-uniform heating of individual joints being welded affects the quality of the resulting weld joints.
The principal object of the invention is to provide a program control device for controlling flash butt welding, which due to analizing signals received from each joint in the course of flashing of abutting ends being joined, ensures a higher efficiency of the welding process and a better quality of the resulting weld joints.
Another object of the invention is to reduce a flashing allowance for the workpieces being welded.
Yet another object of the invention is to decrease that portion of welding time which is caused by an irregular preparation of workpiece edges before weld-ing.
In accordance with a particular embodiment of the invention there is provided a program control device for controlling flash butt welding of several joints ~- simultaneously. The device includes welding circuits, welding current pick-ups connected in each welding cir-cuit, and a logical coincidence means which has inputs to which are applied signals from the outputs of the welding current pick-ups with an output signal of the ~7~
logical coincidence means being produced when the signals are applied to all its inputs. A welding program con-trol means has a power supply circuit which is switched on at the moment when there appears an output signal on the logical coincidence means. A drive means moves the workpieces being welded and being controlled by the welding program control means.
It is expedient that the logic coincidence unit include a logic NAND-gate, a flip-flop, a logic AND-gate, and a relay whose contact which is a control input of the welding program control unit is connected in the power supply circuit thereof, and the winding of which is connected, through the logic AND-gate and the flip-flop, to the output of the logic NAND-gate having inputs connected to the outputs of the welding current pick-ups.
Such embodiment of the invention ensures a high efficiency of the welding process and better quality of the resulting weld joints.
The nature of the invention will be clear from the following description of a specific embodiment thereof taken in conjunction with the accompanying draw-ings~ wherein:
Fig. 1 represents a block diagram of the device of the invention' Fig. 2 represents one of the possible embod-iments of a logical coincidence unit according to the invention.
Workpieces 1 and 2 to be welded together by flash butt welding are clamped by current-carrying jaws - 3 and 4 whereto, through several parallel circuits, is applied voltage from transformers 5. The number of the '~
,~
transformers 5 depends on the length of seams to be formed ana, as practice shows, may reach 10-12. Conn-ected in the welding circuit of each transformer 5 are welding current pick-ups 6.
The welding current pick-ups are intended for producing signals in the presence of a certain current magnitude in a welding circuit. The welding current pick-ups 6 are current transformers having their OUtptlts connected to inputs of rectifiers 8. The rec-tifiers 8 outputs which are the outputs of the welding current pick-ups 6, are connected to inputs of a logical coincidence unit 9 whose output is connected to a con-trol input of a program control unit 10. The device 9 is adpated to start the unit 10 at the moment when along the whole welding circuit the current will reach a certain level.
The program control unit 10 having a power supply circuit 11 is connected through its OlltpUt with a drive 12 adapted for moving the workpieces 1 and 2.
- 20 According to one embodiment of the invention the pro-gram control unit is a multicircuit time relay, and the drive 12 includes an electronic or electromechanical booster, a d.c. motor, a reduction gear, a control sliding valve and a hydraulic cylinder (cf. ~S Patent No. 3,335,257).
In the preferred emhodiment of the invention the logical coincidence unit 9 includes a logic NAND-~` gate 13, a flip-flop 14, a logic A~D-gate 15, and a relay 16 whose contact 17 being a control input of the welding program control unit 10 is connected in the power supply circuit 11 of the unit 10, and whose wind-ing, through the logic AND-gate 15 and the flip-flop 14, is connected to the output of the logic NAND-gate $~ `~?`
13 having its outputs connected to the outputs of the welding current pick-ups 6.
The logic NAND-gate 13 is intended for deliv-ering all the input signals, and the flip-flop 14 is adapted for storing a signal at its output in the absence of a signal at the output of the logic NAND-gate 13.
The logic AND-gate 15 having a high load cap-acity serves as a decoupling network in the case of switching-on of the relay 16.
Such construction of the logical coincidence unit 9 provides for that the moment of the simultaneous arrival of signals at its input is determined with a high precision and the power supply circuit of the unit 10 is switched on at a right moment.
The logical coincidence unit 9 features a high noise immunity since the switching-on of the power supply circuits is effected directly through the output contact of the relay.
The logical coincidence unit 9 may be variously otherwise embodied. It may have, for example, multiple input logic NAND-gate having its output connected to the flip-flop. In this case however, the output of the flip-flop is connected directly to the control input of the program control unit 10 whose construction is based on logic elements, which complicates to a great extent the unit 10, thereby making the unit more costly~
The welding program control device operates as follows. Welding voltage from the transformer 5 is applied, through the current-carrying jaws 3 and 4 to the workpieces 1 and 2. The workpieces 1 and 2 are ,~. !' ~7~
moved towards each other by the drive 12, with the approach speed being controlled by the welding program control unit 10. Starting speed of approach of the workpieces is selected so as to ensure a more rapid flashing of the workpiece butt end irregularities without causing the already flashed parts thereof to be heated until the flashing process takes place along the whole line of the seam to be formed.
In the course of upsetting of the workpieces 1 and 2 the abutting ends thereof begin to fuse down at their different portions, which is caused by irregular-ities resulting from inadequate preparation of the edges i.e. abutting ends of the workpieces 1 and 2, and ~ uneven clamping thereof by the jaws 3 and 4. In this :~ 15 case the welding current will flow in the circuits of only those transformers 5 at the sections of which there takes place contacting and flashing of the abutting edges of the workpieces 1 and 2. As a result, signals in-dicative of the presence of the welding current in a : 20 respective welding circuit are fed to the corresponding inputs of the logical coincidence unit 9, in which case a signal at the output of the unit 9 does not appear.
As indicated above, the logical coincidence unit 9 is constructed so that the output signal is generated only in thé case of presence of signals at all its inputs the number of which is determined by the number of the welding current pick-ups 6.
As the abutting edges of the workpieces 1 and
The present invention relates to ~lash butt welding~ and particularl~ to apparatu~ Por program control of flash butt .velding.
Most efficientl~ the invention can be used in simultaneous-1~ welding several join-ts, as well as in welding articles having long seams to be formed, such a , for example~ metal s~eets measu-ring several meters in width and pipes of large diameters.
'~here is known a program control device ~or controlling a ~lash bu-tt welding process (cf. U~SR Author's Certi~icate ~o. 557~889) comprising welding culren-t pick-ups switched into each welding circuit, and a welding program controlling unit havin~ a power suppl~ circuit and being connec-ted through its output with a drive for moving workpieces being welded. ~his device ~ur-ther includes a peak s;Lgnal de-tector having inpu-ts connected to outputs o~ the welding current pick-ups and an out-put connected, through a parallel-connected proportional and r~al dif~eren-tiating elemen-ts, to a comparator unit.
This prior art device opera-t;es as ~ollows. A preset current magnitude ~rom a pic~-up~ an actual current magnitude, and a time deri~ative thereo~ ara applied to the comparator unit.
'~he ampli~ied signal from the comparator unit is fed to the : welding program con~rol unit controlling the drive ~or moving the woxkpieces being welded. It is to be noted that the speed of approach o~ the wor~pieces is propor-tional to the said signal.
Thus, t~e operation o~ the above device consis-ts in detect-ing a maximal magnitude o~ the current densi-ty in one of t~e parallel circuits, and in controlling the welding process to "~
0~
maintain s-tability thereof bas-ing on the said maximal magnitude of the current density.
However, in the case of using the prior art device, a starting flashing allowance has to be increased.
Moreover the welding time has also to be increased to compensate for an irregular preparation of abutting ends of the workpieces to be welded together, which in the end brings down the efficiency of the welding process.
In addition non-uniform heating of individual joints being welded affects the quality of the resulting weld joints.
The principal object of the invention is to provide a program control device for controlling flash butt welding, which due to analizing signals received from each joint in the course of flashing of abutting ends being joined, ensures a higher efficiency of the welding process and a better quality of the resulting weld joints.
Another object of the invention is to reduce a flashing allowance for the workpieces being welded.
Yet another object of the invention is to decrease that portion of welding time which is caused by an irregular preparation of workpiece edges before weld-ing.
In accordance with a particular embodiment of the invention there is provided a program control device for controlling flash butt welding of several joints ~- simultaneously. The device includes welding circuits, welding current pick-ups connected in each welding cir-cuit, and a logical coincidence means which has inputs to which are applied signals from the outputs of the welding current pick-ups with an output signal of the ~7~
logical coincidence means being produced when the signals are applied to all its inputs. A welding program con-trol means has a power supply circuit which is switched on at the moment when there appears an output signal on the logical coincidence means. A drive means moves the workpieces being welded and being controlled by the welding program control means.
It is expedient that the logic coincidence unit include a logic NAND-gate, a flip-flop, a logic AND-gate, and a relay whose contact which is a control input of the welding program control unit is connected in the power supply circuit thereof, and the winding of which is connected, through the logic AND-gate and the flip-flop, to the output of the logic NAND-gate having inputs connected to the outputs of the welding current pick-ups.
Such embodiment of the invention ensures a high efficiency of the welding process and better quality of the resulting weld joints.
The nature of the invention will be clear from the following description of a specific embodiment thereof taken in conjunction with the accompanying draw-ings~ wherein:
Fig. 1 represents a block diagram of the device of the invention' Fig. 2 represents one of the possible embod-iments of a logical coincidence unit according to the invention.
Workpieces 1 and 2 to be welded together by flash butt welding are clamped by current-carrying jaws - 3 and 4 whereto, through several parallel circuits, is applied voltage from transformers 5. The number of the '~
,~
transformers 5 depends on the length of seams to be formed ana, as practice shows, may reach 10-12. Conn-ected in the welding circuit of each transformer 5 are welding current pick-ups 6.
The welding current pick-ups are intended for producing signals in the presence of a certain current magnitude in a welding circuit. The welding current pick-ups 6 are current transformers having their OUtptlts connected to inputs of rectifiers 8. The rec-tifiers 8 outputs which are the outputs of the welding current pick-ups 6, are connected to inputs of a logical coincidence unit 9 whose output is connected to a con-trol input of a program control unit 10. The device 9 is adpated to start the unit 10 at the moment when along the whole welding circuit the current will reach a certain level.
The program control unit 10 having a power supply circuit 11 is connected through its OlltpUt with a drive 12 adapted for moving the workpieces 1 and 2.
- 20 According to one embodiment of the invention the pro-gram control unit is a multicircuit time relay, and the drive 12 includes an electronic or electromechanical booster, a d.c. motor, a reduction gear, a control sliding valve and a hydraulic cylinder (cf. ~S Patent No. 3,335,257).
In the preferred emhodiment of the invention the logical coincidence unit 9 includes a logic NAND-~` gate 13, a flip-flop 14, a logic A~D-gate 15, and a relay 16 whose contact 17 being a control input of the welding program control unit 10 is connected in the power supply circuit 11 of the unit 10, and whose wind-ing, through the logic AND-gate 15 and the flip-flop 14, is connected to the output of the logic NAND-gate $~ `~?`
13 having its outputs connected to the outputs of the welding current pick-ups 6.
The logic NAND-gate 13 is intended for deliv-ering all the input signals, and the flip-flop 14 is adapted for storing a signal at its output in the absence of a signal at the output of the logic NAND-gate 13.
The logic AND-gate 15 having a high load cap-acity serves as a decoupling network in the case of switching-on of the relay 16.
Such construction of the logical coincidence unit 9 provides for that the moment of the simultaneous arrival of signals at its input is determined with a high precision and the power supply circuit of the unit 10 is switched on at a right moment.
The logical coincidence unit 9 features a high noise immunity since the switching-on of the power supply circuits is effected directly through the output contact of the relay.
The logical coincidence unit 9 may be variously otherwise embodied. It may have, for example, multiple input logic NAND-gate having its output connected to the flip-flop. In this case however, the output of the flip-flop is connected directly to the control input of the program control unit 10 whose construction is based on logic elements, which complicates to a great extent the unit 10, thereby making the unit more costly~
The welding program control device operates as follows. Welding voltage from the transformer 5 is applied, through the current-carrying jaws 3 and 4 to the workpieces 1 and 2. The workpieces 1 and 2 are ,~. !' ~7~
moved towards each other by the drive 12, with the approach speed being controlled by the welding program control unit 10. Starting speed of approach of the workpieces is selected so as to ensure a more rapid flashing of the workpiece butt end irregularities without causing the already flashed parts thereof to be heated until the flashing process takes place along the whole line of the seam to be formed.
In the course of upsetting of the workpieces 1 and 2 the abutting ends thereof begin to fuse down at their different portions, which is caused by irregular-ities resulting from inadequate preparation of the edges i.e. abutting ends of the workpieces 1 and 2, and ~ uneven clamping thereof by the jaws 3 and 4. In this :~ 15 case the welding current will flow in the circuits of only those transformers 5 at the sections of which there takes place contacting and flashing of the abutting edges of the workpieces 1 and 2. As a result, signals in-dicative of the presence of the welding current in a : 20 respective welding circuit are fed to the corresponding inputs of the logical coincidence unit 9, in which case a signal at the output of the unit 9 does not appear.
As indicated above, the logical coincidence unit 9 is constructed so that the output signal is generated only in thé case of presence of signals at all its inputs the number of which is determined by the number of the welding current pick-ups 6.
As the abutting edges of the workpieces 1 and
2 fuse down their edges become more even, and at the moment when the welding current rlows in each circuit of the transformers 5, to all the inputs of the unit 9 will be fed signals from the welding current pick-ups 6, '~"
-7~Z~
in which case at the output of the unit 9 there appears a signal to start the welding program control unit 10.
Thus, a program controlled welding begins at the moment when the workpieces being welded begin to flash off over the whole length of the seam to be formed.
The logical coincidence unit 9 shown in Fig.
2 operates as follows. When signals are applied to all the inputs of the logic NAND-gate 13, at the output thereof there appears a fixed signal which, being applied to the input of the logic AND-gate 15, causes the relay 16 to operate and through its contact 17 to energize the welding program control unit 10.
Beginning from this moment the welding process proceeds under the control of the unit 10.
The proposed device allows the flashing allow-ance to be considerably reduced and the efficiency and quality of welding to be irnproved.
This invention may be variously otherwise embodied withln the scope of the appended claims.
. ~
;' . . . ~ .
-7~Z~
in which case at the output of the unit 9 there appears a signal to start the welding program control unit 10.
Thus, a program controlled welding begins at the moment when the workpieces being welded begin to flash off over the whole length of the seam to be formed.
The logical coincidence unit 9 shown in Fig.
2 operates as follows. When signals are applied to all the inputs of the logic NAND-gate 13, at the output thereof there appears a fixed signal which, being applied to the input of the logic AND-gate 15, causes the relay 16 to operate and through its contact 17 to energize the welding program control unit 10.
Beginning from this moment the welding process proceeds under the control of the unit 10.
The proposed device allows the flashing allow-ance to be considerably reduced and the efficiency and quality of welding to be irnproved.
This invention may be variously otherwise embodied withln the scope of the appended claims.
. ~
;' . . . ~ .
Claims (2)
1. A program control device for controlling flash butt welding of several joints simultaneously, comprising:
- welding circuits;
- welding current pick-ups connected in each said welding circuit, and having outputs;
- logical coincidence means having inputs to which are applied signals from the outputs of said welding current pick-ups, with an output signal of said logical coincidence means being produced when signals are applied to all its inputs;
- welding program control means having a power supply circuit which is switched on at the moment when there appears an output signal of said logical coin-cidence means, and - drive means for moving the workpieces being welded, and being controlled by said welding program control means.
- welding circuits;
- welding current pick-ups connected in each said welding circuit, and having outputs;
- logical coincidence means having inputs to which are applied signals from the outputs of said welding current pick-ups, with an output signal of said logical coincidence means being produced when signals are applied to all its inputs;
- welding program control means having a power supply circuit which is switched on at the moment when there appears an output signal of said logical coin-cidence means, and - drive means for moving the workpieces being welded, and being controlled by said welding program control means.
2. A program control device for controlling flash butt welding of several joints simultaneously, comprising:
- welding circuits;
- welding current pick-ups connected in each said welding circuit, and having outputs;
- logical coincidence means having inputs to which are applied signals from the outputs of said weld-ing current pick-ups, with an output signal of said logical coincidence means being produced when signals are applied to all its inputs and including a logic NAND-gate having inputs the number of which inputs is equal to the number of said welding current pick-ups, and an output at which a signal appears at the moment when signals are applied to all the inputs of said logic NAND-gate, a flip-flop adapted for storing an ouptut signal in the absence of a signal at the output of said logic NAND-gate, and having an input connected to the output of said logic NAND-gate, and an output; a logic AND-gate having an input connected to the output of said flip-flop, and an output; and a relay having a contact switched into the power supply circuit of said welding program control means, and a winding connected to the output of said logic AND-gate, - welding program control means having a power supply circuit which is switched on at the moment when there appears an output signal of said logical coin-cidence means; and - drive means for moving the workpieces being welded, and being controlled by said welding program control means.
- welding circuits;
- welding current pick-ups connected in each said welding circuit, and having outputs;
- logical coincidence means having inputs to which are applied signals from the outputs of said weld-ing current pick-ups, with an output signal of said logical coincidence means being produced when signals are applied to all its inputs and including a logic NAND-gate having inputs the number of which inputs is equal to the number of said welding current pick-ups, and an output at which a signal appears at the moment when signals are applied to all the inputs of said logic NAND-gate, a flip-flop adapted for storing an ouptut signal in the absence of a signal at the output of said logic NAND-gate, and having an input connected to the output of said logic NAND-gate, and an output; a logic AND-gate having an input connected to the output of said flip-flop, and an output; and a relay having a contact switched into the power supply circuit of said welding program control means, and a winding connected to the output of said logic AND-gate, - welding program control means having a power supply circuit which is switched on at the moment when there appears an output signal of said logical coin-cidence means; and - drive means for moving the workpieces being welded, and being controlled by said welding program control means.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000361564A CA1147026A (en) | 1980-10-02 | 1980-10-02 | Program control device for controlling flash butt welding process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000361564A CA1147026A (en) | 1980-10-02 | 1980-10-02 | Program control device for controlling flash butt welding process |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1147026A true CA1147026A (en) | 1983-05-24 |
Family
ID=4118063
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000361564A Expired CA1147026A (en) | 1980-10-02 | 1980-10-02 | Program control device for controlling flash butt welding process |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1147026A (en) |
-
1980
- 1980-10-02 CA CA000361564A patent/CA1147026A/en not_active Expired
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Legal Events
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| MKEX | Expiry |